RU1814663C - Method of making steel thrust-free cone threaded tube joint - Google Patents

Abstract

The invention relates to thermomechanical processing of metals and can be used in any industrial sectors that manufacture threaded joints, metallurgy, mechanical engineering, and the oil industry. SUBSTANCE: prior to thread cutting, torsional deformation is carried out in opposite directions of the ends of the workpieces intended for cutting connection elements under creep conditions at a temperature of 0.2-0.65 of the melting temperature of the materials of the connection elements at a voltage equal to operational, followed by cooling in water or oil, and after cutting the threads between them, a carbide stamp is placed in the form of a thin conical shell with a thread, the size of which is the same as the size of the threaded of compound tightened compound is heated, the loosening, the stamp was removed, screwed again adjusted to the original puff to the last heat. The best option is when torsional deformation is carried out at 400 ° C and a voltage of 6.95 kg / mm2, and at the second heating the temperature of the first heating is repeated - 400 ° C. 1 s, item f. (L C

Description

The invention relates to the field of thermomechanical processing of metals and can be used in any industries manufacturing threaded joints - metallurgy, mechanical engineering, oil industry.

The purpose of the invention is to increase the interchangeability of highly sealed threaded pairs.

Example. We took steel pipe billets of a threaded connection of tubing tubing 73x5.5 of strength group D according to GOST 633-70. Spent

torsional deformation in opposite directions (against screwing) of the ends intended for cutting the joining elements of the workpieces under creep conditions at a temperature of 400 ° C and a voltage of 6.95 kg / mm2, followed by unloading and rapid cooling with water. The deformation was carried out at the VNIITneft STK-8000 stand. Thus, 10 pairs of tubing billets 73x5.5 were processed. After cutting the corresponding threads on the workpieces, they were screwed and their initial tightness was determined. Over00

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thus, when screwing under a second heating (also up to 400 ° C), a die made of heat-resistant steel 4X5MF1S (EP572) after chemical-heat treatment (nitriding) was placed between the nipple and the coupling of the joint. Then, the connection was tightened with a moment of 1500 Nm, heated, unscrewed, the stamp was removed, screwed again, adjusted to the initial one before the last heating, i.e. until 1500

Prior to treatment, threaded ICT connections were allowed to flow at a pressure of 40 MPa (400 bar). After processing, the elements 10 of the compounds (nipples and couplings) were statistically mixed. Thus obtained 10 compounds with randomly selected elements withstood a pressure of at least 50 MPa (500 atm). Thus, due to reverse creep, which causes force loads, a micro-irregularity of the threaded surfaces of the joint is achieved by means of a stamp, and good (30% higher than untreated joints) interchangeability is achieved.

Claims (2)

1. A method of manufacturing a steel flawless conical threaded pipe connection, including threading on the connection elements, the initial screwing of the elements, characterized in that, in order to increase the interchangeability of high-tight threaded pairs, the ends of the workpieces are heated to 0.2 before threading. .0.65 Tm., Torsional deformation is carried out in the opposite direction to the screw top, and with a voltage equal to the operational one, cool, after the initial make-up, unscrew, place between the elements a threaded carbide conical shell, screwed, the connection is reheated, unscrewed, the shell removed and finally screwed with a tightening equal to the initial one after threading. 2. The method according to claim 1, wherein the heating is carried out under torsional deformation and reheating to 400 ° C, and the deformation is carried out at a voltage of 6.95 to 5 kg / mm. 0 5 0